Shutter device for pressure container

ABSTRACT

A shutter for large pressure vessels comprises a lid assembly (Y) constituted of a seal plate (1) formed of a flexible material of a size fit for the opening of a pressure vessel and a multitude of beam members (2) attached to the outer surface of the plate (1) and extending widthwise. The beam members are connected to the seal plate in such a manner as to be parallel to each other along a reference line for connection, extending in the widthwise direction of the seal plate, and advance or retreat while flexing along a guide member (7) having at least one bending portion (71). The guide member extends between a closing position (A) disposed in front of the opening portion and a storage position (B) disposed on an outer housing of the pressure vessel, so that the assembly can be housed in a relatively small space. This shutter is most suitable for use on a medical autoclave and a retort for food processing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a lid assembly for pressure containers and thecreation of an opening and closing mechanism therefor. A shutter deviceconstructed according to this invention is most suitable for use in apressure container having an internal treating chamber adapted to becontrolled alternately to have a pressurized state and a depressurizedstate.

2. Description of the Related Art

As is known in the art, since lids for pressure containers, such asautoclaves for medical use and retorts for food processing, requirestrength and fluid tightness, they are constructed of relatively thick,heavy-weight members. An opening and closing mechanism connected to sucha lid tends to be a necessarily large-sized rugged structure in order toattain reliability and safety in operation. According to a known lid anda known lid opening and closing mechanism, there is provided a lid bodywhich is sized to suit the opening and the lid body is supported foropening and closing on a support shaft in the lateral surface, so thatwhen the opening is closed, the front ends of a plurality of clampingrods on the lid body engage the peripheral edge of the opening to lockthe entire lid body.

In the field of storage and transport techniques, as shown in JapaneseUtility Model Publication No. 14406 to 1978, there is proposed a liddevice (of the lift type) comprising a dome-shaped lid body adapted tobe lifted from the position in front of the opening in a container to anupper retracted position by a link mechanism including a hydrauliccylinder and a bell crank. Further, as in the case of Japanese UtilityModel Publication No. 21 of 1981, there are some known ones (of theslide type) wherein an angularly shaped lid body is adapted to be movedvertically or horizontally between guide rails on opposite sides of thecontainer through a chain and sprocket device (for example, JapaneseUtility Model Publication No. 45807 of 1974, and Japanese PatentPublication No. 45949 of 1982).

Although these known lid devices are substantially satisfactory instrength, they require a wide space for moving the lid body during theopening and closing operation. Besides these, there are many other knownones which, in the opened state, require a wide storage space for thelid body outside the container. This is a limiting factor in installinga pressure container in a limited space in a factory or facilities,obstructing wide use of large-sized pressure containers.

On the other hand, concerning ideas relating to storage of a lid orshield plate for shielding the opening, there are proposed a shuttermechanism for houses as described in Japanese Utility Model PublicationNo. 41985 of 1980 and a carrier shutter for refrigerator cars as shownin Japanese Utility Model Publication No. 30728 of 1980. They comprise anumber of shutter panels connected in the longitudinal direction(direction of movement), such shutter panels being adapted to be bent atjunctions between adjacent panels during the opening and closingoperation. Therefore, when such shutter panels are used, all panels canbe moved along the outer housing surrounding the shield space until theyare stored compactly in a desired place.

This type of shutter is useful in that the storage space therefor can beminimized, but has received no proper attention as to retention of fluidtightness, particularly pressure resistance in a state where a pressureabove atmospheric pressure is present.

Generally, in the case where a pressure-resistant type lid structure isapplied to a pressure container such as an autoclave for medical use,proper measures must be taken as to the fact that at the same time asthe entire lid body together with the pressure container is pressurized,it is heated as well. In reality, in treatment by an autoclave,sterilization treatment is performed usually at a pressure of 1.5-2.0kg/cm² and a temperature of about 130° C., or drying treatment isperformed at a reduced pressure of about -760 mmHg; therefore, it isrequired that the lid and the lid opening and closing mechanism becapable of resisting both pressurized and depressurized states and havesufficient heat resistance.

SUMMARY OF THE INVENTION

1. Objects of the Invention

This invention has created a novel shutter device for pressurecontainers overcoming the technical problems described above and isintended to provide a bendable lid assembly superior in pressureresistance and capable of retaining sufficient fluid tightness even in aheated environment and also provide an opening and closing mechanismtherefor.

Another object of this invention is to provide a lid assembly adapted tobe smoothly moved from the opening in a pressure container to a storingplace around an outer housing, and stored in a storing chamber ofrelatively small space provided in the place, and also provide anopening and closing mechanism therefor.

Another object of this invention is to provide a lid assembly capable ofretaining a predetermined strength and fluid tightness in both thepressurized state (pressing force) and the depressurized state (suckingforce), and also provide an opening and closing mechanism therefor.

Other objects and features of the invention will be best understood fromthe following description of embodiments of the invention.

2. Features of the Invention

A shutter device constructed according to this invention comprises aseal plate made of plastic material and sized to fit the opening in apressure container, and a number of beam members applied to the outersurface of the seal plate and extending in the direction of the width.This assembly is adapted to advance or retreat while bending along aguide rail having at least one bend and installed to extend between aclosed position in front of the opening and a suitable stored positionon an outer housing.

In the closed position, the assembly is pressed against the opening bysuitable pressing means and functions to close the opening by the actionof cooperation with the seal plate on the opening. In this state, theseal plate is applied to the beam members on the rear surface, with theresult that whether the treating chamber is in the positive pressure orpressurized state or in the negative pressure or depressurized state,fluid tightness is never spoiled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view, partly broken away, schematically showing ashutter device according to this invention;

FIG. 2 is a fragmentary sectional view of the shutter device, takenalong the line II--II in FIG. 1;

FIG. 3 is a fragmentary side view, showing the opening and closingoperation of the shutter device;

FIG. 4 is an enlarged fragmentary view, showing an example of means formoving a lid assembly in the shutter device;

FIG. 5 is a fragmentary sectional view showing an example ofconstruction of the lid assembly;

FIG. 6 is a fragmentary sectional view showing another example ofconstruction of the lid assembly;

FIG. 7 is a fragmentary sectional view showing another example ofconstruction of the lid assembly;

FIG. 8 is a fragmentary sectional view showing yet another example ofconstruction of the lid assembly;

FIG. 9 is a fragmentary sectional view showing still another example ofconstruction of the lid assembly;

FIG. 10 is a fragmentary sectional view showing the operating state ofthe moving means before the opening is closed;

FIG. 11 is a fragmentary sectional view showing the operating state ofthe moving means after the opening is closed;

FIG. 12 is an enlarged sectional view showing an example of pressingmeans for pressing the lid assembly against the opening;

FIG. 13 is a fragmentary sectional view showing the operating state ofthe pressing means before the opening is closed;

FIG. 14 is a fragmentary sectional view showing the operating state ofthe pressing means after the opening is closed; and

FIG. 15 is a fragmentary sectional view showing another example ofconstruction of the pressing means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The attached drawings show preferred embodiments of this inventionapplied to an autoclave for sterilization treatment.

In the drawings, the character (X) denotes an autoclave body as apressure container, including a treating chamber, that is, a sterilizingchamber 8, and a steam chamber 12 surrounding the same to serve as aheat source. At one end of the pressure container, there is an opening 5for taking in and out an object to be sterilized, and a lid assembly (Y)according to this invention is installed to cover the opening 5. Suchlid assembly comprises a flexible thin plate, that is, a seal plate 1,and a number of beam members 2 applied to the outer side of said sealplate; thus, the surface of the thin plate member 1 having no beammembers 2 is pressed against a seal member 10 disposed on the peripheryof the opening, whereby the sterilizing chamber 8 is closed. An exampleof pressing means 60 used therefor will be later described in detailwith reference to FIG. 12 or 15.

The beam members 2 are widthwise connected at portions where theycontact the seal plate 1, with adjacent beam members being in a freestate rather than fixed together. Therefore, when the seal plate 1 isbent, the circumferential clearance between adjacent beam members 2increases, thereby allowing smooth bending of the entire lid assembly.With the arrangement thus made, the lid assembly (Y) can be slidparallel with the lateral wall of the pressure container (in theillustrated embodiment, parallel with the upper wall) through suitableguide means until it is stored.

The numeral 7 denotes a guide member forming a stationary track servingas a guide when the lid assembly (Y) is stored, the guide memberextending between a closed position (A) and a stored position (retractedposition) (B), with a bent position 71 disposed interposed therebetween.In this embodiment, the extension 73 of the guide member 7 is positionedparallel with the outer housing 13 in the upper region of the pressurecontainer; therefore, after the lid assembly (Y) is separated from theopening 5, it moves while changing the configuration of the beam members2 (see FIG. 4), and is retracted to the stored position on the housing13.

The thin plate member 1 is preferably about 1 mm thick and may be madeof spring steel (SKS) or the like superior in durability under repeatedbending. Further, as for the beam members 2, considering strength andweight, shape steel, e.g., H shape steel may be used. In addition, it isdesirable that the central portion of each beam member where thegreatest stress occurs when it is subjected to the internal pressure inthe pressure container be thicker.

In order to open and close the lid assembly (Y), moving means 30, whichmay be manually operated, having a construction suitable for automationis used to move the lid assembly (Y) back and forth in direction. Forexample, as shown in FIG. 4, the opening and closing operation of thelid assembly can be easily automated by a driving mechanism using ageared motor 31 and a chain 32. The connecting construction required forsaid chain 32 and lid assembly is shown in FIGS. 10 and 11.

In FIG. 5, how the seal plate 1 and the beam members 2 are joinedtogether is shown by way of example. In the same figure, fasteners 3each consisting of a bolt and a nut should be such that besides theability to join two members, they are capable of sealing them to preventleakage of pressure. To this end, the seal plate 1, beam members 2 andfasteners 3 are finished with high dimensional accuracy.

FIG. 6 shows another embodiment, in which a cushion member 1' is used toimprove the sealing quality between the seal plate 1 and the beammembers 2.

Further, in an example shown in FIG. 7, a number of seal plates arestacked in multi-layer construction 1a, 1b, 1c, 1d, thereby ensuringincreased durability and smooth bending. In the same figure, the numeral4 denotes an intermediate keep plate.

In an example shown in FIG. 8, an improved seal plate made of elasticmaterial shown at numeral 5 is used to clamp the beam members 2. In thisexample, the proximal end 2' of each beam member 2 is elasticallysupported between adjacent upper portions of the seal plate 5.

Besides these, as shown in FIG. 9, it is preferable to interpose acushion plate 6 between adjacent beam members 2 for cushioning purposes.

In driving the lid assembly (Y) of this invention, the seal plate 1 oran accessory thereto is frequently contacted by the seal member 10opposed thereto and it is desirable to prevent damage particularly tothe seal member 10. In this connection, FIGS. 10 and 11 show urgingmeans 50 for urging the chain 32 to move away from the autoclave body(X), or the opening 5. The urging means 50 comprises a stem memberelastically pressed by a spring 51 in a direction to project outward andconnected to the chain 32 through a bearing member 52 disposed at thefront end. Disposed on the opposite side with respect to the chain 32 isanother bearing member 54 supported by a support 55.

With the arrangement thus made, before the opening is closed, that is,when the lid assembly (Y) is not pressed against the opening 5, chain 32is held by the action of the urging means 50 at a position where thechain contacts the bearing member 54 disposed at the outside position.And the seal plate 1 is positioned integrally with the beam members 2with a predetermined spacing from the opening 5 through a bracket 57extending from the chain 32 and a connector 56 connecting said bracketto the ends of the beam members 2. The spacing should be such that thereis no interference between the inner surface of the seal plate 1 and theseal member 10 or between the fasteners 3 projecting from the seal plate1 and the seal member 10.

FIG. 11 shows the state (pressed state) in which the lid assembly (Y) ispressed against the opening 5 by the action of pressing means 60 to belater described. As is clear from this, when the opening is to beclosed, the chain 32 is pushed toward the body (X) to allow the innersurface of the seal plate 1 to contact the end surface of the sealmember 10. In FIGS. 11 and 12, the numeral 58 denotes the stop surfaceof the body (X) and the numeral 59 denotes an engaging surface opposedto said stop surface.

Next, referring to FIG. 12, there is shown an embodiment of the pressingmeans 60 comprising a set of serrated members 61 and 62. The numeral 65denotes spring members elastically connecting said set of members. Oneof the serrated or cam-like members 61 and 62, or the outside serratedmember 62 in this embodiment, is given a desired amount of movement bythe spring members 65 and is provided with an engaging portion 61' atthe lowermost end thereof. Thus, when the lower end of the lid assembly(Y) abuts against the engaging portion 61' at the final stage where thelid assembly (Y) reaches the closed position, the inside cam-like member61 is somewhat pushed upward together with the lid assembly (Y). As aresult, the inside serrated member 61 is pushed out under the action ofmeshing with the outside serrated member 62, so that the lid assembly isurged toward the opening 5.

FIG. 13 shows the lid assembly (Y) before closing the opening 5, andFIG. 14 shows the subsequent closed of the opening 5. As can beunderstood therefrom, the actual action (pressing force) of the pressingmeans 60 is brought about as the lid assembly (Y) is moved and it iscanceled when retracted from the closed position.

FIG. 15 shows another example of the pressing means for the lid assembly(Y). In this example, said set of cam-like members 61 and 62 arereplaced by a wedge member 68 driven by a cylinder 67 and a pressurereceiving plate 69 engaging said wedge member. The same figure shows theopened state, the closed state not shown.

The shutter device according to this invention has a novel lid assemblydescribed above, capable of retaining sufficient strength and fluidtightness even in heated conditions and produces great industrial meritswhen applied to various pressure containers. Further, the novel lidopening mechanism connected to the lid assembly makes it possible toattain a safe and reliable opening and closing operation and tomanufacture the entire device in compact form.

Further, embodying the shutter device of this invention makes itpossible to reduce the space for moving the lid assembly and the spacefor storing the same. As a result, the limitations on installing the lidassembly are eased to a great extent, allowing the surplus space to beeffectively utilized. Further, the mechanism for opening and closing thelid assembly can be simplified to automate the opening and closingoperation, contributing much to labor saving and safety driving.

Further, because of the merits described above, this inventionencourages wide use of large-sized pressure containers.

Particularly, when applied to autoclaves for medical use or retorts forfood processing whose treating chambers are put in pressurized anddepressurized states, the invention contributes to increased safety andlabor saving.

We claim:
 1. A shutter device for a pressure container having apressurized state and a depressurized state, the shutter comprising:alid assembly including a flexible seal plate having an outer surface,and a number of widthwise extending beam members applied to the outersurface of the seal plate; a stationary guide track for guiding the sealplate for sliding movement between a closed position in which the sealplate overlies an opening of the container, and a stored position inwhich the seal plate is remote from the opening, said guide track havingat least one bend between the closed position and the stored position;moving means for moving the lid assembly along the guide track betweensaid positions; and pressing means for sealingly pressing the lidassembly against the opening of the container in the closed position tomaintain an fluid-tight seal in the pressurized and depressurizedstates.
 2. The shutter device according to claim 1, in which the outersurface of the seal plate is substantially flat, and in which each beammember has a rectangular cross section, said beam members being joinedto the seal plate by fasteners at a number of connecting points arrangedwidthwise of the seal plate.
 3. The shutter device according to claim 1,in which the seal plate is a composite structure and includes a cushionmember thereon.
 4. The shutter device according to claim 1, in which theseal plate is a multi-layer structure and includes multiple members. 5.The shutter device according to claim 1, in which the seal plate isconstituted of an elastic material, and in which the beam members areclamped at uniform intervals on the elastic seal plate.
 6. The shutterdevice according to claim 1, in which the moving means includes a chainextending along the guide track and a geared motor for driving thechain; and further comprising a bracket member and fasteners forconnecting the chain to the beam members.
 7. The shutter deviceaccording to claim 6, in which the moving means includes urging meansfor urging the chain in a direction away from the opening of thecontainer.
 8. The shutter device according to claim 1, in which thepressing means includes a plurality of serrated members.
 9. The shutterdevice according to claim 8, in which the serrated members areelastically connected to one another by a spring member, and in whichone of the serrated members has an engaging portion for urging the lidassembly toward the opening of the container in the closed position. 10.The shutter device according to claim 1, in which the lid assembly ispositioned in a substantially vertical orientation in the closedposition, and in a substantially horizontal orientation in the storedposition.